1. Field of the Invention
The present invention relates to a sport boot of the type that requires a longitudinal mobility of the foot with respect to the leg and a proper retention of the ankle in the transverse direction, such as a boot that is more specifically adapted for walking (trekking), cross-country skiing (skating), or yet for in-line roller skating.
2. Background and Material Information
While such sports require the boot to have front and rear flexibility, i.e., front-rear bending for the foot with respect to the leg, in the direction of displacement, they also require lateral supports as well as a specific support for the ankle in the transverse direction.
To enable lateral support to be provided, sport boots are known, which are constituted by an external sole overlaid by an upper extended at its upper portion by an open rigid collar surrounding the user's ankle, and whose free ends form overlaps or overlapping portions that are positioned on one another to surround, and ensure the lateral holding of, the ankle or of the lower part of the leg (i.e, lower leg portion) of a user, by means of a tightening strap or the like connecting the overlapping portions to one another and provided with means for blockage into position.
However, there has been a lack of efficiency in lateral retention of these collars, because these overlapping portions have a tendency, when support is provided to the right or to the left with respect to the direction of walking, to be subjected to a rotational movement with respect to one another, in a substantially vertical plane, due to the tendency of the collar to twist in either direction.